Studies will be performed on patients with portal hypertension to determine the relationship between the clinical presentation and the splanchnic hemodynamic pattern. Hepatic blood flow and the fraction of portal flow shunted through portasystemic communications from the splenic and superior mesenteric vascular beds will be assessed by an indicator dilution technique utilizing selective catheterization of the hepatic, splenic and superior mesenteric artery and the hepatic vein. Particular attention will be paid to the role of high splenic flow in atients with splenomegaly, the pattern of shunting in patients with renal failure associated with cirrhosis, and the distribution of blood flow in patients with high cardiac output complicating cirrhosis. BIBLIOGRAPHIC REFERENCE: Cohn JN: Hepatocirculatory failure. Med Clin North Am 59: 955-962, 1975.